Titanate nanotube thin films with enhanced thermal stability and high-transparency prepared from additive-free sols

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• 作者：L¨¢szl¨® K?r?si ; Szilvia Papp ; Vikt¨®ria Hornok ; Albert Oszk¨® ; P¨¦ter Petrik ; Daniel Patko ; Robert Horvath ; Imre D¨¦k¨¢ny
• 关键词：Titanate nanotubes ; Thermal stability ; Specific surface area ; Titanate thin films ; Spin-coating
• 刊名：Journal of Solid State Chemistry
• 出版年：2012
• 出版时间：August, 2012
• 年：2012
• 卷：192
• 期：Complete
• 页码：342-350
• 全文大小：2176 K

文摘

Titanate nanotubes were synthesized from TiO₂ in alkaline medium by a conventional hydrothermal method (150 ¡ãC, 4.7 bar). To obtain hydrogen titanates, the as-prepared sodium titanates were treated with either HCl or H₃PO₄ aqueous solutions. A simple synthesis procedure was devised for stable titanate nanotube sols without using any additives. These highly stable ethanolic sols can readily be used to prepare transparent titanate nanotube thin films of high quality. The resulting samples were studied by X-ray diffraction, N₂-sorption measurements, Raman spectroscopy, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The comparative results of using two kinds of acids shed light on the superior thermal stability of the H₃PO₄-treated titanate nanotubes (P-TNTs). X-ray photoelectron spectroscopy revealed that P-TNTs contains P in the near-surface region and the thermal stability was enhanced even at a low (¡«0.5 at % ) concentration of P. After calcination at 500 ¡ãC, the specific surface areas of the HCl- and H₃PO₄-treated samples were 153 and 244 m² g^?1, respectively. The effects of H₃PO₄ treatment on the structure, morphology and porosity of titanate nanotubes are discussed.